The 2016 presidential election will be a struggle between competing visions of the future — as have been all American elections since 1796 — but it may not be just a battle over the direction of the country. More than most elections, it may set one past against another — or, given the emerging character of the Republican race, it may involve three separate, contradictory memories of the past.

The first is the memory of the Bill Clinton 1990s. Scrubbed clean of the controversies over gays in the military, health care, terrorism and presidential impeachment, it now survives, in the view of Democrats at least, as a modern golden age, a fin-de-siecle Renaissance where culture flourished and affluence spread. Raise a dissenting view and Clinton loyalists all have the same response: What exactly about peace and prosperity didn’t you like?

The second is the memory of the George W. Bush years at the beginning of the new century. There is terrorism, of course, but few blame the 43rd president for the attacks on the Pentagon and the World Trade Center and for the deadly plunge of the plane into a Pennsylvania field. Then again, Mr. Bush is pilloried, sometimes as often on the right as on the left, for the financial crisis (and for his response to it) and for the invasion of Iraq on specious grounds (and the conduct of the conflict once the invasion was underway).

These two memories may collide if former Secretary of State Hillary Rodham Clinton and former Florida Gov. Jeb Bush face each other in the 2016 general election. They may even collide as the two fight to win their respective presidential nominations, for already there is unease that the presence of these two figures at the top of their tickets would transform American politics into the sort of dynastic politics at home that the country has always held in contempt abroad.

On the surface, the peace-and-prosperity perspective of the Clinton years trumps the two-wars-and-recession retrospective of the years of the second President Bush. But presidential politics is different from all other aspects of American civic life, drawing on and producing deep emotions, prompting and reflecting deep introspection. The surface perspectives seldom suffice.

For that reason, the rear-view mirror images of the Clinton years are far more complicated. They include the first lady’s attempt to forge and then force through a health care plan, her response to the Whitewater investigation, her betrayal by a husband with a wandering eye and her attacks against what she described, somewhat accurately, as a vast right-wing conspiracy. Those memories of 1993-2001 are full of tumult and upheaval, and for every genial reverie about the Clinton past there is a nightmare memory of the political and cultural bedlam it produced.

Then there is the swiftly changing view of Mr. Bush’s father, George H. W. Bush. This complicates matters on both the Democratic and Republican side.

Few American presidents — surely not Herbert Hoover, Richard Nixon or Jimmy Carter — have enjoyed a flowering of revisionism as swift and as deep as the 41st president. Lyndon Johnson now is regarded far more heroically than he was in his White House years, but the sting of Vietnam remains.

The best comparisons are Harry Truman and Dwight Eisenhower. Mr. Truman’s revival took a quarter-century and can be attributed almost completely to the work of Merle Miller, who re-established the folksy Truman in the American memory, and to David McCullough, who identified depth in Mr. Truman that others had missed.

Gen. Eisenhower remains a duffer golfer president in the American memory, but among scholars his image has soared, mostly because of the revisionist work of Fred I. Greenstein, the Princeton professor whose descriptive phrase “hidden hand presidency” has had remarkable resiliency, and Jean Edward Smith, the Columbia University historian whose heroic 2012 biography is now the standard view of Gen. Eisenhower.

But George H.W. Bush’s revival through revisionism has been of a different nature altogether — organic, spawned by a national sentiment that is more than sentimentality. Today the first President Bush is viewed as a figure of selfless service and chivalric virtues. His conduct of the first Gulf War is regarded as the model of strategic insight, and his personal comportment as the Iron Curtain was lifted across Communist Eastern Europe is regarded as the model of restraint.

Mr. Carter may be the most frenetic former president alive and Mr. Clinton the most prominent, but Mr. Bush is by any measure the most beloved. To be sure, he is still reviled on the right for his compromises to reach the 1990 budget agreement, and there’s no contesting that he broke his read-my-lips vow on taxes. But increasingly that is viewed as a broken campaign promise not unlike the one Franklin Delano Roosevelt made in Pittsburgh in 1932, when he vowed to submit a balanced budget. (Sam Rosenman, the presidential speechwriter, advised FDR to deny he had ever been in Pittsburgh.)

So the nostalgia-warmed memories of Bush 41 are in conflict with the bitter-baked memories of the Bush 43 years, and the man who would be Bush 45 must navigate those difficult shoals.

But just as difficult is the navigation the 42nd president — and the husband of a potential nominee — must perform. In the past decade Bill Clinton, the president between the two Bushes, has become close to the man he dismissed as “old Bush” en route to defeating him in the bitter 1992 election.

As a former president, Mr. Clinton ordinarily would be protective of a fellow tenant of the White House, but Mr. Clinton’s regard for his predecessor is far deeper, a sentiment returned by many members of the Bush family, including Barbara Bush, who once proclaimed, “I love Bill Clinton.”

“Bill’s father wasn’t around,” Mrs. Bush said in a C-SPAN interview last year. “And I think that he thinks of George a little bit like the father he didn’t have, and he’s very loving to him. And I really appreciate that.”

The past is a foreign country, with evolving contours. Today’s presidential candidates must steer their way through a past that is fast-changing, not static. It is a complicated journey, and perhaps more than any American presidential election in history, the coming contest will be determined by a struggle over how the past is redefined.

David Shribman, a Pulitzer Prize winner in journalism, is executive editor of the Pittsburgh Post-Gazette.